Can a Quattro 24V be adapted as a Quattro 48V?

Running a 24V Victron Quattro and sitting here eyeing up a shiny new Fogstar 48V pack like it owes me money.

The classic "series your 24V batteries to hit 48V" trick is tempting, but here's where my methodical brain starts twitching — you cannot just swap a Quattro 24V for a Quattro 48V by rewiring your battery bank. The inverter itself is rated for a specific voltage range; the 24V unit won't thank you for feeding it 48V, it'll just quietly have an existential crisis and probably take your combi fuse with it.

So the real question is: is the Quattro 24V actually adaptable at the hardware level, or are we always talking a full unit swap?

From what I can dig up, Victron don't offer a factory re-flash or hardware mod path between voltage variants — the transformers and MOSFETs are wound/rated differently from the off. Essentially you're looking at a new unit, not a conversion.

My narrowboat setup is crying at the thought of the cost, but the 48V ecosystem (smaller cable runs, better efficiency, more battery options) is genuinely worth it long-term.

Has anyone here actually made this jump — kept their existing Quattro 24V in service somewhere else (garden office, anyone?) whilst moving to a fresh 48V unit? Feels like the only sensible play rather than trying to bodge voltage compatibility that simply isn't there.

Also curious whether anyone's mixed legacy 24V kit alongside a new 48V bank using a DC-DC converter as a bridge — seems like it could work on paper but I'd want someone who's actually done it to talk me out of it first.

Hey @ExPostie86, I feel that pull toward shiny new kit, believe me! 😄

Just to be straight with you though - the Quattro itself is voltage-specific internally. The transformer, MOSFETs, control circuitry - all designed around 24V nominal. You can't simply retune it to accept 48V input, it'd let out the magic smoke pretty sharpish.

The series battery trick is a no-go here too, because you'd still be feeding 48V into hardware rated for 24V max.

Realistically your options are either:

• Sell the 24V Quattro and put the funds toward a proper 48V unit
• Stick with a 24V battery upgrade instead

Victron do have a decent second-hand market, so shifting your current inverter might offset the cost more than you'd expect. Worth checking the usual Facebook groups and eBay before committing either way.

Pretty sure the short answer is no — the 24V and 48V Quattros are fundamentally different units internally, not just firmware variants. The transformer windings, FETs, everything is spec'd for the voltage range it ships with.

Even if you got it "working" somehow, you'd be voiding any warranty and running outside safe operating parameters.

Realistically, has anyone actually priced a second-hand 48V Quattro recently? They pop up on eBay and the Facebook off-grid groups fairly regularly. Might be cheaper than you'd expect, especially if you're already planning the Fogstar pack investment anyway.

What size Quattro are you running currently — the 3kVA or 5kVA? That might affect what your realistic upgrade path looks like cost-wise.

Went down this exact rabbit hole last spring when I was speccing out the cabin build. Spent an embarrassing amount of time convincing myself there had to be some clever workaround.

There isn't.

The transformer windings, MOSFETs, gate drivers — it's all optimised for the specific voltage range. You're not buying a "voltage setting" when you choose a 24V Quattro, you're buying fundamentally different iron.

What I'd actually suggest: sell the 24V unit now while prices are decent, because the second-hand Victron market is still reasonably healthy. Put that toward a proper 48V Quattro and pair it with the Fogstar pack from the off.

Done it right once rather than bodged twice has been my motto since the static caravan cost me twice what it should have. 😅

@ExPostie86 one thing nobody's mentioned yet — even if the hardware could theoretically be bodged, the transformer windings, MOSFET gate drive circuits, and charge algorithm firmware in a 24V Quattro are all optimised for that voltage band. The absorption/float thresholds, temperature compensation curves, the lot. You'd be fighting the unit at every stage.

Practically speaking, the cleanest path is selling the 24V unit and putting that money toward a proper 48V Quattro. Second-hand market for Victron kit is genuinely strong — I shifted my old MultiPlus 24/3000 last year for a decent return on eBay.

Worth checking the Victron compatibility matrix too before assuming any 48V battery will play nicely via the VE.Can or BMS comms — Fogstar's newer packs have improved on this but it's always worth verifying firmware versions first.